Method for producing acetylene



March 12, 1957 J. E. BLuDwoR'n-l 2,785,213

METHOD FOR PRonucING ACETYLENE Filed May 4. 1951 4 sheets-sheet 1 wmf.

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March 12, 1957 J. E. BLuDwoRTH METHOD FOR PRODUCING ACETYLENE 4Sheets-Sheet 2 Filed May 4. 1951 fad I /ENTOK. j. ,f

Much 12, .1957 J, E, BLUDWORTH 2,785,213

METHD FOR PRODUCING ACETYLENE 4 Sheets-Speed; 3

Filed May 4. 1951 March l2, 1957 J. E. BLuDwoFm-x METHOD FOR PRODUCINGACETYLENE 4 Sheets-Sheet 4 Filed May 4, 1951 l I INVENTOR.

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United States Patent METHOD FOR PRODUCING ACETYLENE Joseph E. Bludworth,Corpus Christi, Tex., assignor to Delhi-Taylor Oil Corporation, acorporation of Deiavvare Application May 4, 1951, Serial No. 224,540

9 Claims. (Cl. 260-679) This invention relates to a processv andapparatus for the production of acetylene and more particularly to aprocess and apparatus for the production of acetylene from hydrocarbonssuch as methane. In the past it has been proposed to produce acetyleneby processes involving the subjection of hydrocarbons such as methane tovery high temperature conditions for short periods of time. Suchpreviously employed processes include those in which an electric arc isused to supply the necessary heat for the conversion as well as thoseprocesses in which methane is heated in externally red tubes or ispassed intermittently over hot refractory materials. However, theseprocesses have not been entirely satisfactory because of the expenseinvolved, low conversion rates and inability to produce a trulycontinuous process.

This invention has for an object the provision of a continuous processfor preparing acetylene from hydrocarbons such as methane in which aportion of the heat necessary for the reaction is supplied by thepartial combustion of the hydrocarbon itself.

A further object of this invention is the provision of a readilycontrollable process in which a hydrocarbon, such as methane, and oxygenare mixed in the relatively cool condition and then preheated to anelevated temperature prior to the time that they are subjected to apartial combustion reaction.

A still further object of this invention is the provision of a processthat may be readily controlled to insure that the partial combustion andconcomitant production of acetylene occurs in the reactor and notelsewhere in the equipment.

A still further object of this invention is the provision of a processwhich is carried out in such a manner that a mixture of a hydrocarbon,such as methane, and oxygen may be heated to elevated temperaturesbefore passing to the acetylene-producing reaction section.

A still further object of this invention is the provision of a processand apparatus for heating a mixed stream of oxygen and a hydrocarbon,such as methane, to an elevated temperature without substantialreaction.

A still further object of this invention is the provision of a method ofinitiating a combustion reaction in a reaction chamber in whichacetylene is produced from a hydrocarbon.

A still further object of this invention is the provision of a processand apparatus for preparing acetylenevfrom natural gas.

Further andadditional objects will appear from the followingdescription, the accompanying drawings and the appended claims.

In accordance with one embodiment of this invention, a hydrogen gas,such ask methane, is mixed in a relatively cool condition with oxygen.The cool mixture is then passed at a high linear velocity through atubular coil furnace whereby the stream is heated to a temperaturebetween about l200 and 2000* F., the linear velocity of the stream beingmaintained such that combustion of the methane will notoccur Ywithin thetubular heater.

2,785,213 Patented Mar. 12, 1957 Thereafter the preheated mixture ispassed through an unobstructed enlarged reactor in which partialcombustion of the methane is allowed to occur. This partial combustionresults in the consumption of substantially all of the oxygen andsimultaneously raises the heat of the reaction mixture to a temperaturebetween about 2000 and about 3000 F., thereby converting the unburnedmethane to acetylene. The gases undergoing combustion are passed throughthe reactor at a high linear velocity so that the temperature reachedduring combustion is only maintained for a very short period, i. e.between about 0.001 and about 0.01 second. Thereafter the hot reactedgases containing substantial amounts of acetylene are quenched andsubjected to an acetylene recovery process. As will be more clearlypointed out hereafter, the conditions of the process may be controlledso that the quenched exit gases from the reactor contain in excess of l0percent by volume of acetylene.

Another aspect of this invention resides in the method and means forpreheating a high velocity stream of oxygen and a hydrocarbon underconditions to heat it to a temperature between l200 and 2000" F. underconditions substantially preventing any reaction between the oxygen andmethane therein at the prevailing temperatures. ln accordance with oneembodiment of this invention, this object is achieved by providing apreheater furnace having a pair of lire chambers separated by twoclosely spaced refractory walls. A tubular heating coil for thehydrocarbon-oxygen mixture is placed between the two refractory wallsannd the latter are heated by suitable burners directing llames againstthe opposite outside surfaces thereof. Thus the tubular heating coilbetween the refractory walls is heated solely by radiant heat, therebyinsuring even heating substantially throughout the entire length of thecoil.

For a more complete understanding of this invention, reference will nowbe made to the accompanying drawings, wherein Fig. 1 is a liow planshowing in diagrammatic form an apparatus for carrying out the processof this invention;

Fig. 2 is a broken perspective view showing a preheater furnaceconstructed in accordance with one embodiment of this invention;

Fig. 3 is a vertical sectional view of the preheater furnace shown inFig. 2 taken along the line 3 3 thereof;

Fig. 4 is a top plan view of the preheater furnace shown in Fig. 2 witha portion being shown in section taken along the line 4 4 of Fig. 3; and

Fig. 5 is a sectional view of one embodiment of a reactor or combustionchamber which may be employed for carrying out the process of thisinvention and also illustrating means for quenching the hot reactionproducts.

In carrying out the process of this invention, it is preferred to employnatural gas as the source of methane for the production of theacetylene. Ordinarily dry natural gas may contain about methane andabout 5% of ethane and heavier hydrocarbons. Preferably all of thehydrocarbons heavier than methane are removed from the natural gascharged. To this end and with reference to Fig. l, natural gas (suitablycontaining 95% methane and 5% higher hydrocarbons) is introduced to theapparatus through line 10 into pump l2 wherein it is compressed tobetween 900 and i000 pounds per square inch whereafter it is passedthrough line 14 into the lower portion of a conventional absorber i6.Absorber oil, such as kerosene, is passed into the top of the absorber16 through line 18 and is withdrawn from the absorber through line 20.At the elevated pressure obtaining within the absorber (e. g. 900 to1000 p. s. i. g.) substantially all of the hydrocarbons heavier thanmethane are absorbed by the oil and Substantially pure methane I oxygenmixture.

bustion mixture is then quenched at; once upony discharge from thereactor 64. by means of a convergiugwater Spray supplied through aperforated circular ring 72. The temperature of the. gases is therebyimmediately reduced to. prevent undesirable side reactions., such asexcessive carbon formation and/ or the polymerization of the acetylene.Thereafter the quenched reaction gases are further cooled by passinginto a quench tank 74 andvupwardly through a tower 76 into the top ofwhich cooling water is introduced through line 7S. The tower 76 suitablycontains Raschig rings to provide an effective cooling area and water iscirculated to a cooling tower (not shown) through a line 80 extendingfrom a lower portion of the quench tank. The quenched reaction gasesWithdrawn from the tower 76 through line S2 contain essentiallyhydrogen, carbon monoxide, carbon dioxide, nnreacted methane andacetylene. In order to recover the acetylene,

these gases are pumped by pump Se under pressure Y through line S andthe heat exchanger 83 and -a line 90 to an acetylene absorber 92. Theacetylene absorber liquid may comprise acetone, acetaldehyde,acetonitrile, nitrobenzene, chlorinated hydrocarbons, polyglycols andtheir esters, or any of those that are known in the art for absorbingacetylene from gases of this character. The enriched absorber liquid isdischarged from absorber 92 through line 94 to a suitable acetylenerecovery apparatus (not shown). Tail gases from which substantially allof the acetylene has been removed are withdrawn overhead through line 96and regenerated absorber liquid is passed to the absorber through a line9S.

Animportant feature of this invention is the provision of particulartype of furnace preheater for the methaneit will be borne in mind thatit is preferred, in accordance with the process of this invention asabove described, to preheat the oxygen-methane mixture to a temperaturebetween about 1200" F. and about 2000" F. without initiating acombustion reaction. This can be done by employing a preheater furnaceof the character di'sciosed in Figs. 2, 3 and 4. This furnace comprisesessentially a pair of firingchambers 100 and 102 laterally spaced fromeach other and separated by a pair of spaced refractory walls 1% and 106between which is defined a narrow radiant heating chamber S. 'The walls104 106 are constructed of a highly refractive maaerial such as siliconcarbide which will withstand direct firingat temperatures in excess of3500o F. and which have an extremely high heat transfer rate. Theforward endV wall 110. which is common to the tiring chambers 100 and102 is provided with two vertically spaced rows of apertures M2 throughwhich extend gas pipes or burners E14 connected to a main gas supply116. These burners impinge against odset bricks 113, thereby directingflames in a horizontal direction along the opposing sides of therefractory Walls 204 and- 106. Products of combustion escape from thechimneys 120 and 122. Thus it will be apparent that the flames do notimpinge directly against the preheater coil 52 and local overheatingwhich may cause burning within the tube is thereby avoided. lAlso oxygenof the air does not circulate through the radiant heating chamber incontact with the coil 52. It will be noted from Fig. 4 that thedischarge line 62 is wrapped with insulation 124 to prevent heat lossbetween the pre-- heater and the reactor ed. This insulation material isnot indicated in the. drawing of; Fig. l.

It will be apparent from the foregoing description of the apparatus thatmuch equipment not shown in the drawing will be employed in actualcommercial practice of this invention. Thus the drawings do not showvarious meters, valves, heat exchangers and recording instruments, theuse of which is well known to those skilled in the art and iscontemplated within the scope of this invention.

For a more complete understanding of this invention, reference will nowbe made to. a speeinc. exempte snowing the manner in which the processof this invention may be Carried. 011t- Ii he appreciated, beweren thatthis example is not to be construed Vas the broad aspects of theinvention herein claimed. Streams of oxygen and methane were mixed inthe mixing box 46 without preheating and at ambient temperature (i. e.about 82 E). The methane was fed to the mixing box at the rate of 2,481standard cubic feet per hour and the oxygen was fed at the rate of 1,301standard cubic feet per hour. Thus the volume ratio of oxygen to methanewas approximately l to 2. This relatively cool mixture was then Y"assedinto the line 50 at about 34 pounds per square inch gauge, this pressurebeing suiicient to force the mixture lat an extremely high linearvelocity `through the preheater coil 52. The preheater coil in thisexample comprised a 2O foot length of 3A inch chrome steel alloy tubingin a fore part of thev furnace (up to juncture 5,9) secured to an 11.7foot section of 7/s inch chrome. Asteel tubing beyond juncture 59. Thecoil was serpentine in shape as shown in Fig. 5 and constituted fivepasses. be.- tween the hot refractory walls 104 and 106. These wallswere spaced about 21/2 inches apart forming ,a Barrow radiant heatingchamber about 6l/2 Vfeet long and 3.1/2 feet high. The furnacetenlperature` was adjusted and a small amount of charge gas (24 standardcubic feet per hour) was by-passed through valve. 56 so that the outlettemperature of the furnace was controlled to 1750 F. At this temperaturesubstantially no reaction between the methane and oxygen occurred in thefurnace, this being at least in part due lto the extremely high velocityof the gases forced therethrough, the pressure of the gases at thedischarge end of the preheater being substantially atmospheric. Underthese conditions the velocity of the gas entering the preheating furnacewas about 142,5 linear feet per secondV andthe velocity of the gas atthe outlet end of the preheating furnace wasl about `148,0 linear feetper second. The gaseous mixture heated under these conditions was thenpassed, as abovel described, directly into a 2 inch silicon carbide(Carbofrax) reactor tube which was about 23S/e inches long and whichcontained a thermowell with thermocouples, as indicated ,in Fig, 5. TheNo. 2 thermocouple (T2) was positioned 8 inches from the discharge endof the reactor tube 64j. The silicon carbide electrical resistanceelements '7.0 were heated to a suicient temperature to permit partialcombustion to be maintained within the reactor tube, the gas velocityfrom thev discharge end of the reactor tube being about 348v feet persecond.

Under the conditions indicated, they combustion occurred in the tube 64essentially downstream of the point T1 (see Fig, 5), the temperature atthis point being about 1900" F. The temperature at point 'I g was 2l50F. and the temperature at point T3 was 2700 F. (point Ta being about 3inches from the discharge end of the tube). The average residence time,of the individual gas molecules in the reactor 64 was about 0.0.0813second While the reaction time (residence time between Tg and thequench) was about 0.00219 second. The combustion gases were immediatelyquenchedj with the. converging water spray as above described and theacetylene was recovered from the reaction gases through an acetoneabsorption system. The reaction gases discharged to the quench tower hadtheY following analysis in volume per cent (dry basis):

"the above indicated analysis, indicates. e Yield et acety- Iene,amounting to 216 standard cubic feather haar on Ving necessary for theacetylene-forming reaction.

.nitrogen or other inert gas into the chamber.

7 the basis of 1000 standard cubic feet per hour of methane vfed to theprocess. This is the equivalent of 14.8 pounds of acetylene per1000`standard cubic feet per hour of methane fed to the system.

From the foregoing it is clear that a simple and readily controllableprocess has beenprovided for preparing acetylene from methane. Aparticular feature of the invention involves the stepA of mixing themethane and oxygen while in the relatively cool state and thereafterpreheating them together to obtain a desired pre-combustion temperature.It has been in the past proposed to preheat either the methane or theoxygen before mixing. However, 4where this has been done, the processhas been extremely dificult to control and almostalways the combustionwill eventually occur directly at the mixing point, 'resulting ininefiicient'conversion and rapid disintegrationV of the mixing nozzles.A- further feature of the invention is the `passing of the mixture ofhydrocarbon gas and oxygen through the preheater at an ex'- tremely highvelocity, thus reducing the time factor and permitting a high heattransfer rate in order to prevent undesired combustion from occurringdirectly within the preheater. If combustion is allowed to occur at thispoint,y extremely high temperatures will be generated vwhich. will serveto burn out the coils in short order. On the other hand, it is desiredthat the preheating be carried Yout in a manner to achieve as high atemperature as possible before introducing the preheated stream into thereaction zone. The higher the preheat, the less oxygen -is required inthe mixture to supply the autogenous heat- Likewise, less methane isconsumed in the combustion reaction leaving more gas for acetyleneproduction. A contributing factor in permitting this high heat to beachieved Y without substantial reaction in tthe preheater is theconstruction of the preheater furnace itself as previously described. Inthe modification of the preheater employed inthe specific example givenabove, the silicon carbide refractory walls were spaced about 2% inchesapart and the serpentine coil was spaced therebetween by means ofordinary refractory brick.

In starting up the process, the preheater is tirst fired and theelectrical resistance elements of the reactor are turned'on. Puremethane gas with lor without small quantities of oxygen is thenl passedthrough J'che preheater coil and the reactor until such time as theeffluent from the preheater is in excess of about i200" F. and until theAtemperature at point T2 in the reactor has reached about 2100" F. Theaddition of small amounts of oxygen during the start-up and during theeventual cooling down 'periods seems to increase'the life of the heatingcoils. Thereafter `additional oxygen is slowly introduced into thesystem through line 36 until the optimum concentration has been reachedat the mixing box 46. As the oxygen is introduced, combustion starts inthe reactor to lproduce the desired temperatures. It is important not toallow `the temperature in the reactor to exceed about .3000 F. since thehigher temperatures will result in the formation of an undue amount ofcarbon together with substantial polymerizationrof acetylene. After lthedesired reaction temperature has been obtained, the resistvance elements70 may `be cut out of the vsystem or the collec-t on theY surface of theheating elements 70 perhaps 'due *to* hydrocarbon gases diffusing intothe chamber surrounding the reaction tube VV6,4.

This diiiiculty was eliminated by continuouslyintroducinga small streamof Other means than the electrical resistance elements 70 may be used'to impart external heat to the reactor 64, however,

"electrical resistance heatingv is one of the vfew methods' *capableofireachingsudiciendy high temperatures neces` the reactor.

V8 sary to overcome heat loss. in the apparatus shown when operating inthe range of 2500" to 3000* F.

As indicated inthe foregoing, it is preferable that the exit gases fromthe preheater have a temperature between about 1200 and 2000`iF. and afeature of this invention resides in the discovery that under controlledconditions a mixture of methane and oxygen may be heated to these hightemperatures without reacting.

yBest results have been achieved, however, Where the preheat temperatureis between about 1600 and 1900 P. Likewise, as suggested above,the'combustion temperature should be between about 2000" and 3000Apparently rthe acetylene reaction begins just at about 2000 F. butcarbon formation begins to take over at the temperatures above 3000 F.Temperatures that have been found most suitable for the reactor arewithin the range of 2600 to 2950" F.

if desired, an initiator or promoter, such as propane, acetaldehyde,acetone or the like, may be added in small quantities directly to thereactor tube 64 through line 60 (see Fig. l) whereby to assist incontrolling the combustion therein. f

In order to avoid polymerization of the acetylene that is formed, it ispreferred that the pressure within the reactor be at about atmosphericpressure or even less. Likewise exceedingly short reaction times areimportant, preferably less than 0.01 of a second, suitably between 0.01and 0.001 second, longer times being permissible where lowertemperatures are employed.

As pointed out in the foregoing, this invention iinds primaryapplication in the production of acetylene from natural gas andparticularly from methane. Usually it is preferred to employsubstantially pure methane in order that the operations may bestabilized. The presence of other higher hydrocarbons will have atendency to initiate a combustion reaction in the preheatercoil whichis4 undesirable. Also for this reason, the adsorber 24 is employed toprevent higher hydrocarbon materials (e. g. absorber `oil vapors)V fromgetting into the preheater coil.

\ On the other hand, after the methane-oxygen stream has been preheatedto the optimum amount, it may be de sirable under certain conditions toadd an initiator, such as acetaldehyde or acetone or a higherhydrocarbon (ethane, propane, etc.), in order to assist the combustionin the reactor 64. l Such Van initiator is useful in starting thecombustion reaction and maintaining itin Such an initiator may be added,as suggested above, by means of line 60 directly into the reactor 64through a suitable opening (not shown) in the end plate 66.

In large scale commercial oper-ations the use of the resistance elements70 or other heating means may be dispensed with entirely after thereaction has been started since, Where heat losses `are not too rapid,the appropriate temperatures may be maintained by the partial combustionin the reactor. IIt is, of course, readily apparent that heating means,other than electrical resistance elements, may be employed whennecessary for the reactor tube 64.

`It will also be understood that the process of this in-V vention, inits broader aspects, Vis applicable to other hydrocarbon gases, such asethane or propane. However, if such gases are used, either alone or inadmixture with methane, lower preheat temperatures than those suggestedabove may be necessary.

While particular embodiments of this invention are suggested above, itwill be understood, of course, that the invention is not to be limitedthereto, since many modifications may be made, andv it is contemplated,therefore, by the appended claims, to cover any such modiications asfall within the true spirit and scope ofthis invention. y

'I claim: Y.,

1. Aprocess of producing acetylene from a normally gaseous" hydrocarbonwhich comprises mixing gaseous 21ans-,a is

streams of oxygen and said hydrocarbon, the amount'of 'oxygen in theresulting mixture being less than that required for the completecombustion of the hydrocarbon, heating the resulting mixture in a iirstelongated coniined stream to a temperature between about 1600 and about1900 F., said stream moving at a high linear velocity under conditionsfo prevent substantial combustion of the hydrocarbon therein, thenpassing the heated stream through an enlarged reaction zone at a highlinear velocity less than the linear velocity of said iirst stream andin the absence of a substantial amount lof free hydrogen separatelypassed into said zone, partially combusting said mixture in saidreaction zone at a temperature in excess of about 2000" F., the averageresidence time of the molecules undergoing reaction at saidlast-mentioned temperature being less than about 0.01 second wherebysubstantial quantities of acetylene are produced, immediately quenchingthe reacted mixture after said residence time, and separating acetylenefrom the quenched reaction mixture.

2. A process of producing acetylene from methane which comprises mixingrelatively cool gaseous streams of oxygen and methane, the amount ofoxygen in the resulting mixture being less than that required for thecomplete combustion of the methane, passing the resulting cool mixturethrough an elongated heating coil at a high linear velocity underconditions to prevent substantial combustion of methane therein, heatingsaid mixture in said coil to a temperature between about 1600 yand about1900" F., maintaining the linear velocity of said mixture through saidcoil at a value suicient to prevent said substantial combustion ofmethane, then passing the heated stream through an enlarged reactionzone at a high linear velocity less than the linear velocity of thestream discharged from said coil and in the ab sence of a substantialamount of free hydrogen separately passed into said zone, partiallycombusting said mixture in said reaction zone at a temperature in excessof about 2000" F., the average residence time of the moleculesundergoing reaction at said last mentioned temperature being less thanabout 0.01 second whereby substantial quantities of acetylene areproduced, immediately quenching the reacted mixture after said reactiontime has elapsed, and separating acetylene from the quenched reactionmixture.

3. A process of producing acetylene involving the partial combustion ofmethane which comprises mixing relatively cool streams of oxygen andsubstantially pure methane, thereafter introducing the mixture at highlinear velocity into an elongated externally heated coil, heating thestream in the coil and simultaneously controlling the l'mear velocity ofthe stream therethrough whereby the temperature of the stream is raisedto between about 1600 and 1900 F. and no substantial reaction betweenthe oxygen and the methane is allowed to occur therein, thereafterpassing the thus heated stream into an enlarged reaction zone in theabsence of a substantial amount of free hydrogen separately passed intosaid zone, electing a partial combustion of the mixture in said zone ata temperature between about 2000" and about 3000 F., maintaining theaverage residence time of the molecules at said reaction temperature fora period of between about 0.001 and 0.01 second whereby substantialquantities of acetylene are formed, immediately quenching .the partiallycombusted mixture after said residence time, and separating acetylenefrom the quenched mixture.

4.-A process of producing acetylene from natural gas containing methaneand higher hydrocarbons which comprises separating substantially puremethane from said higher hydrocarbons, mixing in a relatively cool statea stream of said methane with a stream of oxygen, the amount of oxygenbeing less than that required to effect a complete combustion of themethane, passing the combined stream through an elongated coil preheaterat a high velocity to prevent a combustion reaction within the coil,discharging the substantially unreacted gaseous which comprises passinga relatively cool stream comprising a mixture of a major proportion byvolume of methane and a minor proportion by volume of oxygen through anelongated radiantly heated tubular coil whereby the mixture is heated toa temperature between about 1600 and about 1900 F., said stream having asuiciently high linear velocity in said coil to prevent substantialreaction of the oxygen with the methane therein, discharging said heatedstream into an enlarged refractory tubular reaction zone through whichsaid gases also pass at a high linear velocity and in the absence of asubstantial amount of free hydrogen separately passed into said zone,maintaining combustion of said mixture within said reaction zone wherebythe temperature of the gaseous mixture is raised to between about 2600and about 2950" F., maintaining said last mentioned temperature for ashort period of time not exceeding about 0.01 second, thereafterquenching the hot reaction gases, and separating therefrom the acetylenethus produced.

6. A process for the production of acetylene from methane whichcomprises passing a stream of a mixture of methane and oxygen through anelongated tubular coil positioned between a pair of closely spacedrefractory walls, firing opposite outside surfaces oi' said wallswhereby said coil is heated externally from opposite sides solely byradiant heat, said stream being heated in said coil to a temperaturebetween about 1600 and about 1900 F., owing said stream through saidcoil at a high linear velocity sufficient to prevent substantialreaction between the oxygen and the methane within the coil at saidtemperature, and then passing said stream through an enlarged reactionzone in the absence of a substantial amount of free hydrogen separatelypassed into said zone to eiect partial combustion of methane andconversion to acetylene.

7. In a process for the production of acetylene by the partialcombustion of methane, the steps of passing a mixture of methane andoxygen at a high linear velocity through an elongated tubular coil,heating said tubular coil under high rate of heat transfer conditionssolely by radiant heat whereby localized heating of said coil withattendant tendency to develop hot spots therein is substantiallyprevented, discharging the heated mixture in the substantially unreactedstate from said coil at a temperature between about 1600 and about 1900F. to a reaction zone, and combusting said mixture in said zone in theabsence of a substantial amount of free hydrogen separately passed intosaid zone at a temperature between about 2000 and about 3000 F.

8. A process of producing acetylene involving the partial combustion ofmethane which comprises mixing relatively cool streams of oxygen andsubstantially pure methane, thereafter passing the mixture through anelongated externally heated coil, heating the mixture in said coil to atemperature of the order of 1750 F. while maintaining the linearvelocity of said mixture through said coil sutiiciently high to preventsubstantial reaction between said oxygen and said methane within saidcoil, thereafter discharging the thus heated mixture at a linearvelocity of the order of 1480 feet per second into an enlarged reactionzone and in the absence of a substantial amount of free hydrogenseparately passed into said zone eiecting a. part'nal combustion ot themixture inY saidzoneat a temperature .between about 2600 andY about 2950F., maintaining the: average, residence time ofthe moleculesf at saidkreaction temperature for a periodrof timeless than about 0.01 secondwhereby substantial quantities of acetylene `are formed, immediatelyquenching the partially combusted mixture after said residence time, andseparating acetyleney from the quenched mixture.

9. A process of producing acetylene from a narmally gaseous hydrocarboncomprising Vessentially methane which comprisesmixing relatively coolgaseous streams of oxygen and said hydrocarbcui,V the amount of oxygenin the resulting mixture being less than that required for the completecombustion o the hydrocarbon, passing the resulting relatively colmixture'into an elongated heating coilheating` the mixture in said coilby means of exten nallyl applied heat to a temperature between about1600 and about 1900a F., maintaining Vthe linear velocity of the mixturein said coil suicient to prevent substantial combustion of thehydrocarbon therein, then passing the heated-mixture into anenlarged'reaction zone at a somewhat` reduced high linear velocity inthe absence of a substantial` amount of free hydrogen separately passedinto said zone, partially combusting said mixture in said reaction zoneat a temperature between about 2000 and y about 3000 F., the averageresidence time of the molequenching fthe reaction mixture, and'separating acetylene therefrom.'

References Cited the tile of this patent' `UN1TED STATES PATENTS1,272,059- Lacy 'July 9,

V1,940,209 Fischerei al.V Dec. 19,1933 1,965,770 Y BurginV July' 10,1934 2,030,070 Morrell Feb. v11, 1936 2,195,227 Sachsse' Mar. 26, 1940'2,196,767` Hasche Apr. 9,1940 2,235,749 Klein et al. Mar. 1,87, 19412,236,555. Wulflk Apr'. 1,Y 1941V 2,325,588 Brandt' A-Llg. 3, 19432,349,439 Koppers May 23, 1944 2,466,617 Spring Apr. 5, 1949 2,498,444Orr Feb.Y 21,` 1950 2,541,471 Hull et al. Feb. 13', 1951 2,556,196Krejci June 12, 1951 2,664,450 Sachsse et al. Dec.,29, 1953l 2,672,488Jonesv Mar. 16, 1954 2,679,540 Berg May 25, 1954

1. A PROCESS OF PRODUCING ACETYLENE FROM A NORMALLY GASEOUS HYDROCARBONWHICH COMPRISES MIXING GASEOUS STREAMS OF OXYGEN AND SAID HYDROCARBON,THE AMOUNT OF OXYGEN IN THE RESULTING MIXTURE BEING LESS THAN THATREQUIRED FOR THE COMPLETE COMBUSTION OF THE HYDROCARBON, HEATING THERESULTING MIXTURE IN A FIRST ELONGATED CONFINED STREAM TO A TEMPERATUREBETWEEN ABOUT 1600* AND ABOUT 1900* F., SAID STREAM MOVING AT A HIGHLINEAR VELOCITY UNDER CONDITIONS TO PREVENT SUBSTANTIAL COMBUSTION OFTHE HYDROCARBON THEREIN, THEN PASSING THE HEATED STREAM THROUGH ANENLARGED REACTION ZONE AT A HIGH LINEAR VELOCITY LESS THAN THE LINEARVELOCITY OF SAID FIRST STREAM AND IN THE ABSENCE OF A SUBSTANTIAL AMOUNTOF FREE HYDROGEN SEPARATELY PASSED INTO SAID ZONE, PARTIALLY COMBUSINGSAID MIXTURE IN SAID REACTION ZONE AT A TEM-